1. CGE Greenhouse Gas Inventory Hands-on Training Workshop WASTE SECTOR

2. Overview Introduction
IPCC 1996GL (Revised 1996 IPCC Guidelines for National Greenhouse Gas Inventories) and GPG2000 (Good Practice Guidance and Uncertainty Management in National Greenhouse Gas Inventories)
Reporting framework
Key source category analysis and decision trees
Tier structure, selection and criteria
Review of problems
Methodological issues
Activity data
Emission factors
IPCC 1996GL category-wise assessment and GPG2000 options
Examination and assessment of activity data and emission factors: data status and options
Uncertainty estimation and reduction

3. Introduction

4. Introduction
COP2 adopted guidelines for preparation of initial national communications (decision 10/CP.2)
IPCC guidelines used by 106 NAI Parties to prepare national communications
New UNFCCC guidelines adopted at COP8 (decision 17/CP.8) provided improved guidelines for preparing GHG inventory
UNFCCC User Manual for guidelines on national communications to assist NAI Parties in using latest UNFCCC guidelines
Review and synthesis reports of NAI inventories highlighted several difficulties and limitations of using IPCC 1996GL (FCCC/SBSTA/2003/INF.10)
GPG2000 addressed some of the limitations and provided guidelines in order to reduce uncertainties
National communications preparation is an evolving process.
New UNFCCC guidelines and GPG2000 have created new possibilities to surpass difficulties and limitations that have been flagged.
UNFCCC’s User Manual for the Guidelines on National Communications from Non‑Annex I Parties is a new tool that needs to be considered.
COP = Conference of the Parties
IPCC = Intergovernmental Panel on Climate Change
NAI = non-Annex I Party (Party not included in Annex I to the Convention)
UNFCCC = United Nations Framework Convention on Climate Change
GHG = greenhouse gas(es).

5. Purpose of this Handbook
GHG inventories are mostly biological sectors, such as Waste, and characterized by:
methodological limitations
lack of data or low reliability of existing data
high uncertainty
This handbook aims at assisting NAI Parties in preparing GHG inventories using the IPCC 1996GL, particularly in the context of UNFCCC decision 17/CP.8, focusing on:
the need to shift to GPG2000 and higher tiers/methods to reduce uncertainty
complete overview of the tools and methods
use of IPCC inventory software and EFDB
review of AD and EF and options to reduce uncertainty
use of key sources, methodologies and decision trees
This handbook is a tool to overcome the complexities of a sector like Waste, that has both biological processes as a simple chemical process (namely incineration).
EFDB = IPCC emission factor database
AD = activity data
EF = emission factor

6. Target groups NAI inventory experts
National GHG inventory focal points

7. NAI country examples
Review of national communications: Argentina, Colombia, Chile , Cuba and Panama
GHG inventories show that the Waste sector may be significant in NAI countries
Commonly a significant source of CH4
In some cases a significant source of N2O
Solid waste disposal sites (SWDS) frequently a key source of CH4 emissions
Waste sector is relevant in countries with large urban populations, particularly in countries with cities that have more than one million inhabitants (that is the case for all the above mentioned countries).
As the main source is generally methane (CH4) emissions from solid waste disposal sites, this gas is the most relevant.
In countries with low agricultural and industrial emissions, the waste sector may also become a significant source of nitrous oxide (N2O).
Analysis of national communications has shown that methane emissions from solid waste disposal sites is commonly a key source

8. Definitions
Waste emissions – Includes GHG emissions resulting from waste management activities (solid and liquid waste management, excepting CO2 from organic matter incinerated and/or used for energy purposes).
Source – Any process or activity that releases a GHG (such as CO2, N2O, CH4) into the atmosphere.

9. Definitions (2)
Activity Data – Data on the magnitude of human activity, resulting in emissions during a given period of time (e.g. data on waste quantity, management systems and incinerated waste).
Emission Factor – A coefficient that relates activity data to the amount of chemical compound that is the source of later emissions. Emission factors are often based on a sample of measurement data, averaged to develop a representative rate of emission for a given activity level under a given set of operating conditions.

10. IPCC 1996GL and GPG2000
Approach and steps

11. Emissions from waste management
Decomposition of organic matter in wastes (carbon and nitrogen)
Waste incineration (these emissions are not reported when waste is used to generate energy)
There are two types of processes associated with waste management:
Rotting
Burning
In the first case, the emissions come from (anaerobic) decomposition occurring slowly and liberating carbonaceous and nitrogenous substances.
In the second case, emissions include carbon dioxide, due to the oxidation processes involved.

12. Decomposition of waste
Anaerobic decomposition of man-made waste by methanogenic bacteria
Solid waste
Land disposal sites
Liquid waste
Human sewage
Industrial waste water
Nitrous oxide emissions from waste water are also produced from protein decomposition
The decomposition of waste is a biochemical process triggered by micro-organisms.
In this slide, the processes (source, process and emissions) that lead to the different emissions are pointed out.

13. Land disposal sites
Major form of solid waste disposal in developed world
Produces mainly methane at a diminishing rate taking many years for waste to decompose completely
Also carbon dioxide and volatile organic compounds produced
Carbon dioxide from biomass not accounted or reported elsewhere
Characteristics of this category are presented here:
Type of activity
Characteristics of the process
Emissions produced
Accounting issues

14. Decomposition process
Organic matter into small soluble molecules (including sugars)
Broken down to hydrogen, carbon dioxide and different acids
Acids are converted to acetic acid
Acetic acid with hydrogen and carbon dioxide are substrate for methanogenic bacteria
In this slide, additional details of the decomposition process are presented in order to help explain the basic biochemistry of the process.
This is relevant for the correct interpretation of the influence of physical factors in the process.

15. Methane from land disposal
Volumes
Estimates from landfills: 20–70 Tg/yr
Total human methane emissions: 360 Tg/yr
From 6% to 20% of total
Other impacts
Vegetation damage
Odours
May form explosive mixtures

16. Characteristics of the methanogenic process
Highly heterogeneous
However, relevant factors to consider:
Waste management practices
Waste composition
Physical factors

17. Waste management practices
Aerobic waste treatment
Produces compost that may increase soil carbon
No methane
Open dumping
Common in developing regions
Shallow, open piles, loosely compacted
No control for pollutants, scavenging frequent
Anecdotal evidence of methane production
An arbitrary factor, 50% of sanitary land filling, is used
Practices that are not fully represented in the IPCC 1996GL or the GPG2000 are presented in this slide.
These practices are common in NAI countries and are here to raise the debate on the approaches used to deal with them.

18. Waste management practices (II)
Sanitary landfills
Specially designed
Gas and leakage control
Scale economy
Continued methane production
In this slide, the characteristics of proper landfills are presented.
This slide is here to remind that in many NAI countries these conditions are not fully achieved.

19. Waste composition Degradable organic matter can vary
Highly putrescible in developing countries
In developed countries, due to higher paper and card content, less putrescible
This affects stabilization and methane production
Developing countries: 10–15 years
Developed countries: more than 20 years
This slide stresses the importance of waste composition as a factor in methane production.

20. Physical factors Moisture essential for bacterial metabolism
Factors: initial moisture content, infiltration from surface and groundwater, as well as decomposition processes
Temperature: 25–40°C required for a good methane production
In this slide, the stress is on the importance of physical factors, essentially moisture and temperature.
The slide is a reminder of the influence of weather on methane production.

21. Physical factors (II) Chemical conditions Conclusion
Optimal pH for methane production: 6.8 to 7.2
Sharp decrease of methane production below 6.5 pH
Acidity may delay the onset of methane production
Conclusion
Data availability is too poor to use these factors for national or global methane emissions estimates
In this slide, the uncertainty related to chemical conditions is presented as an important factor limiting accuracy.

22. Methane emissions Depend on several factors
Open dumps require other approaches
Availability and quality of relevant data

23. Waste-water treatment
Produces methane, nitrous oxide and non-methane volatile organic compounds
May lead to storage of carbon through eutrophication

24. Methane emissions from waste-water treatment
From anaerobic processes without methane recovery
Volumes
30–40 Tg/yr
About 8%–11% of anthropogenic methane emissions
Industrial emissions estimated at 26–40 Tg/yr
Domestic and commercial estimated at 2 Tg/yr
In this slide, an idea of the importance of the source category is presented.
Also, the importance of the industrial waste-water subcategory is stressed.

25. Factors for methane emissions
Biochemical oxygen demand (BOD) (+/+)
Temperature ( >15°C)
Retention time
Lagoon maintenance
Depth of lagoon ( >2.5 m, pure anaerobic; less than 1 m, not expected to be significant, most common facultative 1.2 to 2.5 m – 20% to 30% BOD anaerobically)
In this slide, the particular characteristics of methane emissions from waste water are presented. Note that they are different than those for solid waste.

26. Biochemical oxygen demand
Is the organic content of waste water (“loading”)
Represents O consumed by waste water during decomposition (expressed in mg/l)
Standardized measurement is the “5-day test” denoted as BOD5
Examples of BOD5:
Municipal waste water 110–400 mg/l
Food processing – mg/l
The concept of biochemical oxygen demand is essential for understanding the decomposition processes in water.

27. Main industrial sources
Food processing:
Processing plants (fruit, sugar, meat, etc.)
Creameries
Breweries
Others
Pulp and paper

28. Waste incineration Waste incineration can produce:
Carbon dioxide, methane, carbon monoxide, nitrogen oxides, nitrous oxides and non-methane volatile organic compounds
Nevertheless, it accounts for a small percentage of GHG output from the waste sector

29. Emissions from waste incineration
Only the fossil-based portion of waste to be considered for carbon dioxide
Other gases difficult to estimate
Nitrous oxide mainly from sludge incineration
Particularities concerning waste incineration are raised:
Combustion of biomass-based matter not to be accounted
Nitrous oxide a product of incineration of protein-rich organic matter (sludge)

30. IPCC 1996GL Basis of inventory methodology for waste sector is:
Organic matter decomposition
Incineration of fossil origin organic material
Does not include concrete calculations for the latter
Organic matter decomposition covers:
Methane from organic matter in both liquid and solid wastes
Nitrous oxide from protein in human sewage
Emissions of non-methane volatile organic compounds are not covered

31. IPCC default categories
Methane Emissions from Solid Waste Disposal Sites
Methane Emissions from Wastewater treatment
Domestic and Commercial Wastewater
Industrial Wastewater and Sludge Streams
Nitrous oxide from Human Sewage
From IPCC 1996GL.

32. Inventory preparation using IPCC 1996GL
Step 1: Conduct key source category analysis for Waste sector where:
Sector is compared to other source sectors such as Energy, Agriculture, LUCF, etc.
Estimate Waste sector’s share of national GHG inventory
Key source sector identification adopted by Parties that have already prepared an initial national communication, have inventory estimates
Parties that have not prepared an initial national communication can use inventories prepared under other programs/projects
Parties that have not prepared any inventory, may not be able to carry out the key source sector analysis
Step 2: Select the categories
This and the next slide present an algorithm that is valid for any sector, and it is here for the sake of completeness.

33. Inventory preparation using IPCC 1996GL (2)
Step 3: Assemble required activity data depending on tier selected from local, regional, national and global databases, including EFDB
Step 4: Collect emission/removal factors depending on tier level selected from local/regional/national/global databases, including EFDB
Step 5: Select method of estimation based on tier level and quantify emissions/removals for each category
Step 6: Estimate uncertainty involved
Step 7: Adopt quality assurance/control procedures and report results
Step 8: Report GHG emissions
Step 9: Report all procedures, equations and sources of data adopted for GHG inventory estimation

34. Calculation of methane from solid waste disposal
For sanitary landfills there are several methods:
Mass balance and theoretical gas yield
Theoretical first order kinetics methodologies
Regression approach
Complex models not applicable for regions or countries
Open dumps considered to emit 50%, but should be reported separately
Calculation methods proposed for this source category in IPCC 1996GL.

35. Mass balance and theoretical gas yield
No time factors
Immediate release of methane
Produces reasonable estimates if amount and composition of waste have been constant or slowly varying, otherwise biased trends
How to calculate:
Using empirical formulae
Using degradable organic content
This simple method, used in several cases by NAI countries, gives good approximate results if decomposition conditions are optimal.

36. Empirical formulae
Assumes 53% of carbon content is converted to methane
If microbial biomass is discounted it reduces the amount emitted
234 m3 of methane per tonne of wet municipal solid waste
This is the simplest method.

37. Using degradable organic content (Base of Tier 1)
Calculated from the weighted average of the carbon content of various components of the waste stream
Requires knowledge of:
Carbon content of the fractions
Composition of the fractions in the waste stream
This method is the basis for the Tier I calculation approach
This calculation method requires more knowledge about the waste stream composition, but this is easily obtainable.

38. Equation Methane emission =
Total municipal solid waste (MSW) generated (Gg/yr) x
Fraction landfilled x
Fraction degradable organic carbon (DOC) in MSW x
Fraction dissimilated DOC x
0.5 g C as CH4/g C as biogas x
Conversion ratio (16/12) ) – Recovered CH4
This equation presents all the factors relevant to calculate the emissions of methane using the simple method.

39. Assumptions
Only urban populations in developing countries need be considered; rural areas produce no significant amount of emissions
Fraction dissimilated was assumed from a theoretical model that varies with temperature: T , considering a constant 35°C for the anaerobic zone of a landfill, this gives 0.77 dissimilated DOC
No oxidation or aerobic process included
Notice the relationship between the amount of DOC dissimilated fraction and temperature, indicating the influence of one physical factor on the process.

40. Example Waste generated 235 Gg/yr % landfilled 80 % DOC 21
% DOC dissimilated 77
Recovered Gg/yr
Methane = (235*0.80*0.21*0.77*0.5*16/12) – 1.5 =19 Gg/yr

41. Limitations Main: DOC dissimilated too high
No time factor
No oxidation considered
DOC dissimilated too high
Delayed release of methane under increasing waste landfilled conditions leads to significant overestimations of emissions
Oxidation factor may reach up to 50% according to some authors, a 10% reduction is to be accounted
This slide lists the major caveats that restrict the wider application of this simple method.

42. Default method – Tier 1
Includes a methane correction factor according to the type of site (waste management correction factor). Default values range from 0.4 for shallow unmanaged disposal sites (> 5m) to 0.8 for deep (<5m) unmanaged sites; and 1 for managed sites. Uncategorized sites given a correction factor of 0.6
The former DOC dissimilated was reduced from 0.77 to , due to the presence of lignin
This slide and the following four slides present the improvements introduced to this calculation by GPG2000, leading to the Tier 1 or Default Method.

43. Default method – Tier 1
The fraction of methane in landfill gas was changed from 0.5 to a range between 0.4 and 0.6, to account for several factors, including waste composition
Includes an oxidation factor. Default value of 0.1 is suitable for well managed landfills
It is important to remember to subtract recovered methane before applying an oxidation factor

44. Default method – Tier 1 Good Practice
Emissions of methane (Gg/yr) =
[(MSWT*MSWF*L0) -R]*(1-OX) where
MSWT= Total municipal solid waste
MSWF= Fraction disposed at SWDS
L0 = Methane generation potential
R = Recovered methane (Gg/yr)
OX = Oxidation factor (fraction)

45. Methane generation potential
L0 = (MCF*DOC*DOCF*F*16/12 (GgCH4/Gg waste))
where:
MCF = Methane correction factor (fraction)
DOC = Degradable organic carbon
DOCF = Fraction of DOC dissimilated
F = Fraction by volume of methane in landfilled gas
16/12 = Conversion from C to CH4

46. Other approaches Include a fraction of dry refuse in the equation
Consider a waste generation rate (1 kg per capita per day for developed countries, half of that for developing countries)
Use gross domestic product as an indicator of waste production rates
This slide presents some approaches that may be used when activity data indicate different conditions.

47. GPG2000 Approach

48. Theoretical first order kinetics methodologies (Tier 2)
Tier 2 considers the long period of time involved in the organic matter decomposition and methane generation
Main factors:
Waste generation and composition
Environmental variables (moisture content, pH, temperature and available nutrients)
Age, type and time since closure of landfill
Here, the main differences between Tier 1 and Tier 2 are highlighted.

49. Base equation QCH4 = L0R(e-kc - e-kt)
QCH4 = methane generation rate at year t (m3/yr)
L = degradable organic carbon available for
methane generation (m3/tonne of waste)
R = quantity of waste landfilled (tonnes)
k = methane generation rate constant (yr-1)
c = time since landfill closure (yr)
t = time since initial refuse placement (yr)
In this base equation, the time relationship is evident – variables “c” and “t”.

50. Good practice equation
Time t is replaced by t-x, normalization factor that corrects for the fact that the evaluation for a single year is a discrete time rather than a continuous time estimate
Methane generated in year t (Gg/yr) = Sx [(A*k*MSWT(x)*MSWF(x)*L0(x)) * e-k(t-x) ] for x = initial year to t
Sum the obtained results for all years (x)
The good practice equation introduced here gives a clear idea of the dynamics and additional to the calculation process.

51. Good practice equation
Where:
t = year of inventory
x = years for which input should be added
A = (1-e-k)/k; normalisation factor which corrects the summation
k = Methane generation rate constant
MSWT (x)= Total municipal solid waste generated in year x (Proportional to total or urban population if no rural waste collection)
L0(x) = Methane generation potential
This slide lists the required factors.

52. Methane generation rate constant
The methane generation rate constant k is the time taken for the DOC in waste to decay to half its initial mass (half-life)
k = ln2/t½
This requires historical data. Data for 3 to 5 half lives in order to achieve an acceptable result. Changes in management should be taken into account
The methane generation rate constant is the keystone of Tier 2.
A good understanding of this factor is vital for the proper application of Tier 2.
Proper calculation of “k” is essential.

53. Methane generation rate constant
Is determined by type of waste and conditions
Measurements go from 0.03 to 0.2 per year, equivalent to half lives from 23 to 3 years
More degradable material and humidity lower half life
Default value: 0.05 per year, or a half life of 14 years
The slide presents the factors upon which “k” depends.
Through careful evaluation of national circumstances, values can be generated to replace the default values.

54. Methane generation potential
L0(x) = (MCF(x)*DOC(x)*DOCF*F*16/12 (GgCH4/Gg waste))
where:
MCF(x) = Methane correction factor in year x (fraction)
DOC (x) = Degradable organic carbon in year x
DOCF = Fraction of DOC dissimilated
F = Fraction by volume of methane in gas generated from landfill
16/12 = Conversion from C to CH4
This slide repeats the previously stated concept of methane generation potential, and it is here in the interest of completeness.

55. Methane emitted
Methane generated minus methane recovered and not oxidized
Equation:
Methane emitted in year t (Gg/yr) = (Methane generated in year t (Gg/yr) - R(t))*(1 - Ox)
Where:
R(t) = Methane recovered in year t (Gg/yr)
Ox = Oxidation factor (fraction)
The slide presents additional factors that determine REAL emissions.
Recovery and oxidation and the order in which to deal with them are included here.

56. Practical applications
Base for Tier 2 approach
Applied earlier in:
United Kingdom
The Netherlands
Canada
The countries that have used this equation.

57. Regression approach From empirical models
Statistical and regressional analysis applied
Another possible but uncommon calculation route is briefly introduced here.

58. Uncertainties in calculations
Methane actually produced
Are old landfills covered?
Quantity and composition of landfilled waste
Is there historical data on waste composition?
Are landfill and waste management practices well known?
Key uncertainties relating to SWDS emissions.

59. Calculations of emissions from waste-water treatment
Calculations for industrial and domestic and commercial waste water are based on biochemical oxygen demand (BOD) loading
Standard methane conversion factor 0.22 Gg CH4/Gg BOD is recommended
For nitrous oxide and methane it is possible to base calculation on total volatile solids and apply the simple method used in the agriculture sector
The basic assumptions relating to methane and nitrous oxide emissions from waste-water treatment.

60. Methane from domestic and commercial waste water
Simplified approach
Data:
BOD in Gg per 1000 persons (default values)
Country population in thousands
Fraction of total waste water treated anaerobically (0.1–0.15 as default)
Methane emission factor (default 0.22 Gg CH4/Gg BOD
Subtract recovered methane
The slide presents the use of a simplified approach for domestic and commercial waste water.
This method is efficient for most countries.

61. Equation Methane emission = Population (103) x Gg BOD5/1000 persons x
Fraction anaerobically treated x
0.22 Gg CH4/Gg BOD –
Methane recovered

62. GPG 2000 Approach

63. Good practice guidance – Check method
WM = P*D*SBF*EF*FTA*365*10-12 , where:
WM = country’s annual methane emissions from domestic waste water
P = population (total or urban in developing countries)
D = organic load (default 60 g BOD/person/day)
SBF = fraction of BOD that readily settles, default = 0.5
EF = emission factor (g CH4/ g BOD), default = 0.6 or 0.25 g CH4/ g COD (chemical oxygen demand) when using COD
FTA = part of BOD anaerobically degraded, default = 0.8
GPG2000 includes a simple calculation for methane from waste water. It is called the “check method” and its factors, including its default values, are presented in this slide.

64. Check method rationale
SBF is related to BOD from non-dissolved solids, which account for more than 50% of BOD. Settling tanks remove 33% and other methods 50%
Fraction of BOD in sludge that degrades anaerobically (FTA) is related to the processes, aerobic or anaerobic. Aerobic processes and sludge non-methane producing procedures may lead to FTA = 0
For the basis of this method, see the factors presented on slide 25.

65. Check method rationale
Emission factor is expressed in BOD, however COD is used in many places
COD is 2 to 2.5 times higher than BOD, so the default values are 0.6 g CH4/ g BOD or 0.25 g CH4/ g COD
Emission factor is calculated from the methane producing factor stated above and the weighted average of methane conversion factor (MCF)
A comparison of BOD and COD is presented here. This is important with respect to the prevailing measurement practices.
Methane conversion factor (explained on the next slide) is introduced.

66. Methane conversion factor
IPCC guidelines recommends to separate calculations for waste water and sludge. This influences the detailed approach calculation
Excepting sludge sent to landfills or for agriculture, this is not necessary
If no data are available, expert judgement of sanitation engineers may be incorporated: Weighted MCF = Fraction of BOD anaerobically degrades
First, the approach of IPCC 1996GL is challenged by the first two statements.
The use of expert knowledge is stressed by the last statement.

67. Detailed approach Considers two additional factors:
Different treatment methods used and total waste water treated using each method
MCF for each treatment
The final result is the sum of the fractions calculated by the simplified approach, less the recovered methane

68. Equation Domestic and commercial waste-water emissions =
(Si Methane calculated by simplified approach x
Fraction waste water treated using method i x MCF for method i) - methane recovered

69. Methane emissions from industrial waste water
Industrial waste water may be treated in domestic sewer systems or on site
Only on-site calculations are covered in this section, the rest should be added to domestic waste-water loading
Most estimates used are for point sources
Focus on key industries is required and default values are provided
Some important characteristics of industrial waste waters are stressed:
On site calculations ONLY
Keep the focus on KEY industries

70. Emissions from industrial waste-water treatment
Simplified approach:
Determine relevant industries (wine, beer, food, paper, etc.)
Estimate waste-water outflow (per tonne of product, or default)
Estimate BOD5 concentration (or default)
Estimate the fraction treated
Estimate methane emission factor (default Gg CH4/Gg BOD )
Subtract any methane recovered

71. Equation Industrial waste-water emissions =
(Si waste-water outflow by industry (Ml/yr) x
kg BOD5/I x
Fraction waste water treated anaerobically x 0.22) - Methane recovered
The equation version of the algorithm from the previous slide is presented here.

72. Detailed approach
Similar to the used for estimating methane emissions from domestic and commercial waste water
Requires knowledge of:
Specific waste-water treatments
MCF for each factor
Notice the similarities with slides 67 and 68.

73. Equation Industrial waste-water Emissions =
(Si Waste-water outflow by industry (Ml/yr) x
kg BOD5/l x
Fraction waste water treated using method i x MCF for method i) - Methane recovered
This slide presents the equation derived from the previous slide.

74. Uncertainties in calculations
Lack of information about volumes, treatments and recycling
Discharge into surface waters:
Not anaerobic (default 0%)
Anaerobic (default 50%)
Septic tanks (long retention times: more than 6 months)
Long retention of solids (default 50%)
Short retention of solids (default 10%)
Open pits and latrines (default 20%)
Other limitations: BOD, temperature, pH and retention time
Key uncertainties for waste-water treatment emissions are presented here.

75. GPG2000 Approach

76. Emissions from waste incineration
For carbon dioxide, only fossil fraction counts not biomass
Only accounted under waste sector when no energy is recovered
IPCC guidelines include a simple method
It is good practice to disaggregate waste into waste types and take into account burn-out efficiency of incinerator
In this slide, the main characteristics of waste incineration accounting are presented.

77. Equation for carbon dioxide
CO2 emission (Gg/yr) = Si(IWi*CCWi*FCFi*Efi*44/12)
where i = MSW, HW, CW, SS
MSW municipal solid waste, HW hazardous waste, CW clinical waste and SS sewage sludge
IWi = Amount of incinerated waste type i
CCWi = Fraction of C content in waste type i
FCFi = Fraction of fossil C in waste type i
EF = Burn-out efficiency of combustion of incinerators for waste type i (fraction)
44/12 = Conversion from C to CO2
The equation for carbon dioxide stresses the need to differentiate the four types of waste: municipal, hazardous, clinical and sludge.

78. Equation for nitrous oxide
N2O emission (Gg/yr) = Si(IWi*Efi)*10-6 where
IWi = Amount of incinerated waste type i (Gg/yr)
EFi = Aggregate emission factor for waste type i (kg N2O/Gg) or
N2O emission (Gg/yr) = Si(IWi*ECi*FGVi)*10-9
ECi = N2O emission concentration in flue gas from waste of type i (mg N2O /Mg)
FGVi = Flue gas volume by amount of incinerated waste type i (m3/Mg)
In this slide presente two equations for calculting nitrous oxide emissions, depending on the data available:
First equation uses emission factor
Second equation uses nitrous oxide emission concentration in flue gas

79. Emission factors and activity data for carbon dioxide
C content varies: sewage sludge, 30%; municipal solid waste, 40%; hazardous waste, 50%; and clinical waste, 60%.
It is assumed that there is very little <<virtually no>> fossil carbon in sewage sludge, 0%; high content in clinical and municipal, 40%; and very high content in hazardous waste, 90%
The efficiency of combustion is 95% for all waste streams, except hazardous, which is 99.5%
This slide presents the major assumptions used in calculating carbon dioxide emissions from waste incineration.

80. Emission factors and activity data for nitrous oxide
Emission factors differ with facility type and type of waste
Default factors can be used
Consistency and comparability are difficult due to heterogeneous waste types across countries
The particularities of nitrous oxide calculation are stressed. The calculation must take into account the composition of waste and the incineration process.

81. Reporting framework

82. General reporting recommendations
It is good practice to document and archive all information required to produce the national inventory estimates
See GPG2000, Chapter 8, Quality Assurance and Quality Control, Section , Internal Documentation and Archiving
Transparency in activity data and the possibility to retrace calculations are important
Here, the most common general reporting recommendations are presented.

83. Report quality assurance/quality control
Transparency can be improved through clear documentation and explanations
Estimate using different approaches
Cross check emission factors
Check default values, survey data and secondary data preparation for activity data
Cross check with other countries
Involve industry and government experts in review processes
Here, the most common QA/QC reporting recommendations are presented.

84. Reporting for methane from solid waste disposal sites
If Tier 2 is applied, historical data and k values should be documented, and closed landfills should be accounted for
Distribution of waste (managed and unmanaged) for MCF should be documented
Comprehensive landfill coverage, including industrial, sludge disposal, construction and demolition waste sites is recommended
Notice the importance of “k” value (methane generation rate constant), waste composition and comprehensiveness of the assessment.

85. Reporting for methane from solid waste disposal sites
If methane recovery is reported an inventory is desirable. Flaring and energy recovery should be documented separately
Changes in parameters should be explained and referenced
Time series should apply the same methodology; if there are changes it is required to recalculate the entire time series to achieve consistency in trends (See GPG2000, Chapter 7, , Alternative recalculation techniques)
In this slide, major issues to do with reporting on this source category are stressed: Separation between flaring and recovery, documentation of parameter changes and time series consistency.

86. Reporting for methane from domestic waste-water handling
Function of human population and waste generation per person, expressed as biochemical oxygen demand
If in rural areas, only aerobical disposal; only urban population is accounted for
COD*2.5 = BOD
Recalculate whole time series
Calculations need to be retraced, particularly if there are changes to MCFs
Some key details on reporting are presented here for review.
COD = chemical oxygen demand.

87. Reporting for methane from industrial waste-water handling
Industrial estimates are accepted if they are transparent and consistent with QA/QC
Recalculations need to be consistent over time
Default data for industrial waste water is in GPG2000, Chapter 5, Table 5.4
Sectoral tables and a detailed inventory report are necessary to provide transparency
Some key details on reporting are presented here as reminders.

88. Reporting nitrous oxide emissions from waste water
Based on IPCC Guidelines, Chapter 4, Agriculture, Section 4.8, Indirect N2O emissions from nitrogen used in agriculture
Future work on data, approaches and calculations is needed
Parties are recommended to review the above-mentioned section of the Guidelines to check if the method is applicable according to national circumstances.

89. Reporting for waste incineration
All waste incineration is to be included
Avoid double counting with energy recovery, even when waste is used as a substitute fuel (e.g. cement and brick production)
Default ranges for emission estimates are provided in GPG2000, Chapter 5, Tables 5.6 and 5.7
Support fuel, generally little, shall be reported in Energy sector; maybe important for hazardous waste
The issues related to EF default values and the relationship between the source category and the Energy sector are highlighted here.

90. Key source category analysis and decision trees

91. Comparison

92. Comparison between IPCC 1996GL and GPG2000
IPCC 1996GL - default approach
First Order Decay Method for Solid Waste Disposal Sites based on real- world conditions of decomposition
Based on last year’s waste entering the disposal sites. Good approximation only for long-term stable conditions. First Order Decay is mentioned without specific calculations
Includes a “check method” for countries with difficulties to calculate the emissions from domestic waste-water handling
Keeps a separation between:
Domestic waste water
Industrial waste water
Human sewage is indicated as an area for further development and no improvement over IPCC 1996GL is presented
Calculation made on the basis of an approximation developed for the Agriculture sector (see chapter on Agriculture sector)
New section including emissions from waste incineration covers:
CO2 emissions
N2O emissions
Contains no detailed methodologies <<correct?>>
In several cases GPG 2000 provides a better and simpler calculation tool than does IPCC 1996GL.

93. Key activity data required for GPG2000 and IPCC 1996GL
Disposal activity for solid waste for several years
Less requirements with the check method for CH4 emissions from domestic waste water
Top-down modification of IPCC 1996GL recommended due to high costs
Incineration amounts, composition (carbon content and fossil fraction) required for CO2
Emission measurements recommended for N2O
Disposal activity for current year, default values or a per capita approach
Waste-water flows and waste-water treatment data required
Very detailed, industry specific data required
No specific methodology

94. Key emission factors required for IPCC 1996GL and GPG2000
Most emission factors are common to both:
Methane generation potential for SWDS
Human sewage conversion factor
Methane conversion factor
New emission factors related to:
Tier 2 for SWDS, particularly k value
Waste incineration (lack of some default values)

95. Link between IPCC 1996GL and GPG2000
GPG2000 uses the same tables as were provided in IPCC 1996GL, based on the same categories
This slide is just meant to draw attention to the fact that no new tables were introduced in GPG2000..

96. List of problems

97. Problems addressed Problems found by NAI experts in using IPCC 1996GL
Problems categorized into:
Methodological issues
Activity data (AD)
Emission factors (EF)
GPG2000 addresses some deficiencies found in IPCC 1996GL
Strategies for improvement in methodology, AD and EF
Strategy for AD and EF – tier approach
Points to sources of data for AD and EF, including EFDB
This slide, introduces the problems found, categorizes them and proposes approaches to deal with them.

98. Methodological issues
Methodologies that are not covered :
Sludge spreading and composting,
Use of burning under conditions not reflected properly in the waste incineration section
Tropical conditions of many NAI Parties vis-à-vis methane generation
Use of open dumps instead of landfills
Lack of a proper calculation method for human sewage in the case of island countries or countries with prevailing coastal populations, and complexity of the methodology.
Lack of coverage of issues relevant to NAI countries is presented here.

99. Lack of waste methodologies that reflect national circumstances
GPG2000 approach
Improvement suggested
The GPG2000 does not cover composting and sludge spreading, which are common practices in NAI countries
Burning and open dump processes are not well covered by GPG2000 and are frequent practices in NAI countries.
- Initiate field studies to generate methodologies, or use approaches proposed by Annex 1 countries for these categories.
- Expand the proper sections to reflect the conditions prevailing in many NAI countries.
Some suggestions to lacks or gaps identified are proposed.

100. More deficiencies in the methodologies
GPG2000 approach
Improvement suggested
- The GPG2000 does not cover conditions for tropical countries and management practices for both solid wastes and waste waters
- The approximation used in GPG2000 to calculate nitrous oxide from human sewage (the same approximation as in IPCC 1996GL) does not reflect properly the situation of coastal/island areas
- Initiate field studies to expand the methodology
- Adopt the proposed methodologies covered in the Agriculture chapter differentiating according to geographical reality
Some suggestions to fix deficiencies.

101. Complexity of methodology
GPG2000 approach
Improvement suggested
- The methodologies presented for Solid Waste Disposal Sites and Waste Incineration require data that are not commonly available in NAI countries
- Methods similar to the Check method for waste water should be provided to enhance completeness of reporting

102. Activity data problems
Lack of data on generated solid waste
Lack of time-series data for waste generation
Lack of availability of disaggregated data
Lack of data on composition of solid waste
Lack of data on oxidation conditions
Extrapolations based on past data used to apply Tier 2 for Solid Waste Disposal Sites CH4 generation
Low reliability and high uncertainty of data

103. Emission factor problems
Inappropriate default values given in IPCC 1996GL
Default data not suitable for national circumstances
Lack of emission factors at disaggregated level
Lack of availability of methane conversion factors for certain NAI regions
Low reliability and high uncertainty of data
Lack of emission factors in IPCC 1996GL for waste incineration (covered by GPG 2000)
Default data commonly provides upper value, leading to overestimation

104. List of problems (Category wise)

105. CH4 Emissions from Solid Waste Disposal Sites Table 6.A

106. Methodological issues
Use of open dumps or open incineration
Recycling, commonly of wood and paper but even of organic waste
Some methodological issues not properly covered by the Table 6.A.

107. Activity data and emission factors
Lack of activity data, both for the present and the required time series, for the waste flows and their composition
Default activity data for only 10 NAI countries
Values reflected for k parameter for the application of the First Order Decay method do not reflect tropical conditions of temperature and humidity. The higher k value in GPG2000 is 0.2 and the one in IPCC 1996GL is 0.4
The proposed Methane Correction Factor, even using the lesser value, 0.4, may lead to overestimations, due to shallowness and the frequent practice of burning as a pretreatment at disposal sites
Common problems related to AD and EF for NAI countries.

108. Emissions from Wastewater Handling Table 6.B

109. Methodological issues
For CH4 emissions from domestic waste-water handling, GPG2000 presents a simplified method called the “check method” avoiding the complexities in IPCC 1996GL
In NAI countries, national methods or parameters, or even activity data, may by available only infrequently
For CH4 emissions from industrial waste-water handling, GPG2000 presents a “best practice” for cases where these emissions represent a key source, recommending the selection of 3 or 4 key industries
For emissions of N2O from human sewage, no improvements were made in GPG2000 over IPPC 1996 GL. This methodology has several limitations that have caused several NAI countries to declare it “inapplicable”

110. Activity data and emission factors
Availability of activity data and emission factors is uncommon in NAI countries for CH4 emissions from domestic waste water, and the “check method” may help to overcome this issue. In any case, GPG 2000 is an improvement in that it identifies potential CH4 emissions
For CH4 emissions from industrial waste water, in cases where it is a key source, it is feasible to work only with the largest industries
For N2O emissions from human sewage, the activity data needed are relatively simple and easy to obtain

111. Emissions from Waste Incineration Table 6.C

112. Methodological issues
This source category was only briefly introduced in the IPCC 1996GL, but is fully developed in the GPG2000
In NAI countries, incineration of waste (other than clinical waste) is uncommon due to high costs
Differentiation is made between CO2 and N2O because the former is calculated with a mass balance approach and the latter depends on operating conditions

113. Activity data and emission factors
GPG2000 recognizes the difficulties in finding activity data to differentiate the four proposed categories (municipal, hazardous, clinical and sewage sludge)
Do not request differentiation if data are not available when it is not a key source category
This slide presents an approach for dealing with AD scarcity.

114. Review and assessment of activity data and emission factors: data status and options

115. Status of EFDB for the Waste sector
EFDB is an emerging database
All experts are expected to contribute to EFDB.
Currently it contains only limited information on Waste sector emission factors
In future, with contributions from experts around the world, EFDB should become a reliable source of data for emission factors for GHG inventory

116. EFDB – Waste sector status
IPCC 1996GL category
Emission factor records
Solid Waste Disposal on Land (6A)
115
Wastewater Handling (6B)
191
Waste Incineration (6C) 47
Other (6D)
Total (as at October 2004)
353

117. Uncertainty estimation and reduction

118. Uncertainty estimation and reduction
The good practice approach requires that estimates of GHG inventories be accurate
they should neither be over- nor underestimated as far as can be judged
Causes of uncertainty could include:
unidentified sources
lack of data
quality of data
lack of transparency

119. Reporting uncertainties from solid waste disposal sites
Main uncertainty sources:
Activity data (total municipal waste MSWT and fraction sent to disposal sites MSWF)
Emission factors (methane generation rate constant)
Other factors listed in GPG2000, Table 5.2:
Degradable organic carbon, fraction of degradable organic carbon, methane correction factor, fraction of methane in landfill gas
Possibly also methane recovery and oxidation factor

120. Reporting uncertainties from domestic waste-water handling
Uncertainties are related to BOD/person, maximum methane producing capacity and fraction treated anaerobically (data for population has little uncertainty (+5%))
Default ranges are:
BOD/person and maximum methane producing capacity (+ 30%)
For fraction treated anaerobically use expert judgement
BOD = biochemical oxygen demand

121. Reporting uncertainties from industrial waste-water treatment
Uncertainties are related to industrial production, COD/unit waste water (from -50% to +100%), maximum methane producing capacity and fraction treated anaerobically
Default ranges are:
industrial production (+ 25%)
maximum methane producing capacity (+ 30%)
For fraction treated anaerobically use expert judgement

122. Reporting uncertainties from waste incineration
Activity data uncertainty on amount of incinerated waste assumed to be low (+5%) in developed countries. Some wastes, such as clinical waste, may be higher
Major uncertainty for CO2 is fossil carbon fraction
For N2O default values, uncertainty is as high as 100%